Fix some build symbol configuration.

Fix some build symbol configuration.

Remove -gdwarf-4 from GYP build. This is the default for GCC 4.8 which is now required, so this command-line argument is redundant.

Only set use_debug_fission in the GN build in debug mode. This matches GYP. Release mode symbols will be non-fission.

Implement linux_symbols target in GN. Convert dump_app_syms from sh to Python for better GN usability, and it's more readable for normal programmers on the team.

BUG=

Committed: https://crrev.com/950889c01dd934acf28bce29ea6db75610a8c441
Cr-Commit-Position: refs/heads/master@{#334510}

[brettw, 2015-06-15 21:04:37]

brettw@chromium.org changed reviewers:
+ thakis@chromium.org

[brettw, 2015-06-15 21:04:38]

I verified that a GYP official release build chrome and the dumped chrome symbol
file do not change with the addition of this patch.

[Nico, 2015-06-15 21:13:40]

lgtm, but:

https://codereview.chromium.org/1179393004/diff/20001/build/linux/dump_app_sy...
File build/linux/dump_app_syms.py (right):

https://codereview.chromium.org/1179393004/diff/20001/build/linux/dump_app_sy...
build/linux/dump_app_syms.py:26: shell=True)
shell=True is only needed for the "> outfile" bit, right? Does this work?

  with open(outfile, 'w') as outfileobj:
    subprocess.check_call([dumpsyms, '-r', infile], stdout=outfileobj)

Then you don't need the ' '.join and the shell=True and the additional shell
subprocess.

[brettw, 2015-06-15 22:26:10]

https://codereview.chromium.org/1179393004/diff/20001/build/linux/dump_app_sy...
File build/linux/dump_app_syms.py (right):

https://codereview.chromium.org/1179393004/diff/20001/build/linux/dump_app_sy...
build/linux/dump_app_syms.py:26: shell=True)
Nifty, thanks.

[brettw, 2015-06-15 22:26:15]

The CQ bit was checked by brettw@chromium.org

[brettw, 2015-06-15 22:26:15]

The patchset sent to the CQ was uploaded after l-g-t-m from thakis@chromium.org
Link to the patchset: https://codereview.chromium.org/1179393004/#ps40001
(title: "review comments")

[commit-bot: I haz the power, 2015-06-15 22:28:44]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1179393004/40001

[commit-bot: I haz the power, 2015-06-16 00:25:15]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-06-16 00:26:10]

Patchset 3 (id:??) landed as
https://crrev.com/950889c01dd934acf28bce29ea6db75610a8c441
Cr-Commit-Position: refs/heads/master@{#334510}

[Lei Zhang, 2015-06-16 01:09:46]

A revert of this CL (patchset #3 id:40001) has been created in
https://codereview.chromium.org/1182783006/ by thestig@chromium.org.

The reason for reverting is: Broke the Linux GN Clobber bot:

http://build.chromium.org/p/chromium.linux/builders/Linux%20GN%20Clobber/buil...

ninja: error: '../../build/linux/dump_app_syms', needed by
'obj/chrome/linux_symbols.inputdeps.stamp', missing and no known rule to make
it.